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Thread: midlength buffer?

  1. #31
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    Sorry did not know background, reading threads quickly sometimes is hard to tell if users have any experience w platform first (shooting, cleaning). I can put them together but consider myself in the shooting/cleaning camp so my explanation below is just that:

    If your bolt carrier group (BCG) is not being allowed to move rearward enough, i.e. short stroke, do you want more or less weight in its path? I think these buffer weights are from Robb:
    Carbine 2.9 oz -> 3 steel weights
    H buffer 3.8 oz -> 1 tungsten weight
    H2 buffer 4.6 oz -> 2 tungsten weights
    H3 buffer 5.6 oz -> 3 tungsten weights

    (There are always other variables at play) but hopefully you can visualize how the weight of the buffer might change the rearward motion of the BCG.

    One such variable is ammo. There will be more force moving the BCG rearward using 5.56 compared to commercial 223 loadings. This is what Robb was saying. I would like to give you exact chamber pressure figures for live rounds instead of saying "trust me" but sorry idk them.

    Hope this helps more than my previous post.
    Last edited by nml; 01-24-12 at 13:37. Reason: Singular not plural

  2. #32
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    Quote Originally Posted by nml View Post
    Sorry did not know background, reading threads quickly sometimes is hard to tell if users have any experience w platform first (shooting, cleaning). I can put them together but consider myself in the shooting/cleaning camp so my explanation below is just that:

    If your bolt carrier group (BCG) is not being allowed to move rearward enough, i.e. short stroke, do you want more or less weight in its path? I think these buffer weights are from Robb:
    Carbine 2.9 oz -> 3 steel weights
    H buffer 3.8 oz -> 1 tungsten weight
    H2 buffer 4.6 oz -> 2 tungsten weights
    H3 buffer 5.6 oz -> 3 tungsten weights

    (There are always other variables at play) but hopefully you can visualize how the weight of the buffer might change the rearward motion of the BCG.

    One such variable is ammo. There will be more force moving the BCG rearward using 5.56 compared to commercial 223 loadings. This is what Robb was saying. I would like to give you exact chamber pressure figures for live rounds instead of saying "trust me" but sorry idk them.

    Hope this helps more than my previous post.
    Yes, that actually helps a lot more with the visualization, thanks. For some reason, I was visualizing the action backwards. I was thinking that if the .223 round was causing the short stroke, that adding more mass to the buffer would assist the motion, but can see the error in my thought process now. From the way I understand it now, the heavier buffers actually are used to slow the action down. If that's the case, then it seems as though I should be fine with the carbine for .223 target ammo, but may need the "H" for the m855, or other 5.56 ammo for example - right?

  3. #33
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    Yeah remember the buffer is just sitting there all peaceful and neutral like Switzerland, it's only when you pull the trigger that the gas recoil slams the bolt carrier rearward into the buffer.

    (Not to confuse) but buffer weights are designed to slide around so there's also secondary action going on after it stops rearward on the receiver extension. In summary, I basically leave it to the cool guys w high-speed cameras measuring cyclic rates in various environments to find out what works best.

    When you try out both buffers and have them in front of you, I'm sure you'll be like "What was I worrying about again?"

  4. #34
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    Quote Originally Posted by nml View Post
    Yeah remember the buffer is just sitting there all peaceful and neutral like Switzerland, it's only when you pull the trigger that the gas recoil slams the bolt carrier rearward into the buffer.

    (Not to confuse) but buffer weights are designed to slide around so there's also secondary action going on after it stops rearward on the receiver extension. In summary, I basically leave it to the cool guys w high-speed cameras measuring cyclic rates in various environments to find out what works best.

    When you try out both buffers and have them in front of you, I'm sure you'll be like "What was I worrying about again?"
    I'm sure you are right. This wasn't so much worry as it was excitement and anxiety while waiting for the rest of the parts to finish the build. I was just hoping that I didn't make a mistake that would delay things, so if it was suggested here that the carbine buffer was inadequate, then I would have ordered something else to keep the delays down. I actually feel a lot better now thanks to your explanations, as well as the others. I actually got the parts from PSA today, so I was pretty excited, but they somehow forgot to include the charging handle, so I'm missing a key piece. Since you can never reach them by phone I used their email "form" to let them know of the error, so hopefully they will rectify this soon. I plan to eventually grab a Gunfighter handle for it, but couldn't pass on the deal they had with their premium BCG. It was only $10 extra for the handle. At least it will make a good spare once I upgrade.

  5. #35
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    I'm running an H on my 16" middy. it functions with minimum powder in a 55 grain/ramshot tac load. I don't think i'd go beyond an H in a middy.

  6. #36
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    I've been running an H2 with a 14.5" BCM mid-length for about 1,500 rounds.

    I've ran the gun with very little lube and it's been functioning fine using a variety of Walmart Federal .223 55gr FMJ, American Eagle .223 55gr, FMJ, BVAC .223 55gr FMJ, BVAC .223 62gr FMJ, and dirty Federal XM193f 5.56 without any problems regarding short stroking, failure to lock on empty, etc.

    Now I haven't noticed any damage to the buffer itself on either end besides for a few nicks around the outer edges of the area that's exposed to the bolt carrier. Based on what I've accumulated from reading these boards, any damage to the buffer would essentially result from an over-gassed system and the buffer is moving too fast.

    Knowing that my setup works with that variety so far, should I continue to use the H2 buffer?
    Last edited by contax_shooter; 01-31-12 at 09:54.

  7. #37
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    Quote Originally Posted by contax_shooter View Post
    I've been running an H2 with a 14.5" BCM mid-length for about 1,500 rounds.

    I've ran the gun with very little lube and it's been functioning fine using a variety of Walmart Federal .223 55gr FMJ, American Eagle .223 55gr, FMJ, BVAC .223 55gr FMJ, BVAC .223 62gr FMJ, and dirty Federal XM193f 5.56 without any problems regarding short stroking, failure to lock on empty, etc.

    Now I haven't noticed any damage to the buffer itself on either end besides for a few nicks around the outer edges of the area that's exposed to the bolt carrier. Based on what I've accumulated from reading these boards, any damage to the buffer would essentially result from an over-gassed system and the buffer is moving too fast.

    Knowing that my setup works with that variety so far, should I continue to use the H2 buffer?
    If it works with all types of ammo why would you want to change it?

    Are you running a semi-auto carrier, by chance?
    a former meatpuppet.

    http://sixty-six.org

  8. #38
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    Quote Originally Posted by panzerr View Post
    If it works with all types of ammo why would you want to change it?

    Are you running a semi-auto carrier, by chance?
    Yes, I'm running a semi-auto carrier. All this talk about the different buffers and the way the BCM mid-length systems were designed to use the H buffer was making me second guessing my current configuration.

  9. #39
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    Quote Originally Posted by contax_shooter View Post
    Yes, I'm running a semi-auto carrier. All this talk about the different buffers and the way the BCM mid-length systems were designed to use the H buffer was making me second guessing my current configuration.
    It was designed to be used with an H buffer and a full auto carrier, which is heavier than a semi auto carrier. A semi auto carrier with an H2 must be roughly the same weight as it seems to be working fine for you, even with low power ammo.
    a former meatpuppet.

    http://sixty-six.org

  10. #40
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    Don't overthink this subject like others are doing and you will be fine.



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